1. Field of the Invention
The present invention relates to a method for discriminating the operation type of a disk device, and more particularly to a method used for detecting the horizontal, vertical, or inverse operation type of a disk device, in which a servo unit is affected by different gravities due to different assembly positions, in order to adjust the control performance of the servo unit.
2. Description of the Prior Art
In order to satisfy the application and room demand of various electric products, a disk device needs to be installed on many surfaces with different directions. However, the disk device reads/writes high density marks on a disc with high speed. The slight difference of the gravity acted on the servo unit in the disk device will change the control performance of the servo unit so as to affect the accuracy and efficiency of the disk device.
A conventional pick-up head 1 of a disk device is shown in FIG. 1. The pick-up head 1 includes a seat 2 which individually extends four elastic wires 3 from two sides to connect to two sides of an optical head 4 for supporting the float of the optical head 4. In the center, the optical head 4 carries an objective lens 5 which emits a laser beam onto marks of a disc (not shown) and receives the reflective beam from the disc. Each ends of the optical head 4 individually attaches a magnetic block 6 around which an actuator 7 is mounted. Besides, an L-shaped base plate 8 is extended from the seat 2 to carry the optical head 4. Opposite to the magnetic block 6, each end of the base plate 8 disposes a magnet 9. By the cooperation of the magnetic block 6, the actuator 7 and the magnet 9, the actuator 7 adjusts the magnitude and the direction of magnetic control force to drive the optical head 4. The optical head 4 supported by four wires 3 floats the objective lens 5 along the direction A to adjust the focusing servo, and along the direction B to fine adjust the tracking servo.
Since the disk device is horizontally disposed in general, the control performance affected by the gravity is adjusted only based on the horizontal type. In the direction A, the control force of the optical head 4 is the magnetic control force plus the gravity to achieve the normal control performance. In the direction B, because the gravity is vertical to the magnetic control force, the control force of the optical head 4 is able to normally control the performance without counting the factor of the gravity. When the disk device is disposed in a non-horizontal position, the control performance isn't suitable for the change of the gravity. Therefore, the conventional disk device currently utilizes a mechanical sensor to detect horizontal or vertical operation, but the mechanical sensor needs bigger room and increases the production cost. Another conventional disk device detects horizontal or vertical operation according to the change of focusing voltage to adjust the control performance. The disk device can't further detect the inverse or non-vertical operation and still can't correctly adjust the control performance based on the influence of various gravities, so the conventional disk device doesn't satisfy the demand of various electric products in which the disk device is disposed in various directions. Consequently, the conventional disk device still has the problem of discriminating the operation type to resolve.